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Section 6.3 – Life Substances

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Presentation on theme: "Section 6.3 – Life Substances"— Presentation transcript:

1 Section 6.3 – Life Substances

2 Role of Carbon in Organisms
Carbon (C) has 4 electrons available for bonding C bonds to form single, double, or triple bonds with other atoms

3 Role of Carbon in Organisms
When C-C atoms, can form straight or branched chains, or rings

4 Role of Carbon in Organisms
Isomer Compounds that have the chemical formula but different 3-D structures Examples: C6H12O6 Glucose, Fructose, Galactose

5 Role of Carbon in Organisms
Biomolecules Large organic compounds May consist of 100s or 1000s of C atoms Example: Protein

6 Role of Carbon in Organisms
Polymer Large molecule formed when many smaller molecules bond together Condensation Reaction monomer + monomer = polymer + H2O Hydrolysis polymer + H2O = monomer + monomer

7 Condensation Hydrolysis

8 Carbohydrates Used to provide cells with energy
Biomolecule composed of Carbon, Hydrogen, + Oxygen Found in ratios of 2 H: 1O; the # of C atoms varies

9 Carbohydrates Monosaccharides A building block of a carbohydrate
A simple sugar Most common types: Glucose – used in cells Fructose – found in fruits Galactose – found in milk

10 Carbohydrates Disaccharide “double sugar”
Combination of 2 monosaccharides from a condensation reaction Example: Sucrose

11 Carbohydrates Polysaccharides Composed of many monosaccharides
Examples: Starch Stored as branched chain of glucose Used as energy storage for plant cells Glycogen Stored as highly branched chain of glucose Used as energy storage for animal cells Cellulose Stored as chain-linked branches of glucose Makes up plant cell walls

12 Polysaccharides Examples

13 Lipids Biomolecule composed of C, H, + few O Examples: Fats Oils Waxes

14 Lipids Lipids are insoluble in water because molecules are nonpolar
Not attracted by water

15 Lipids Fatty Acid Long chain of carbon + hydrogen
Building block of lipids Saturated C-C (single bonds) Unsaturated C-C (double bond) Polyunsaturated C-C (many double bonds)

16 Lipids Functions of lipids: Energy storage Insulation
Protective coverings Cell membrane

17 Proteins Functions: Provide structure for tissues + organs Carries out cell metabolism Large, complex polymer composed of C, H, O, Nitrogen (N), + Sulfur (S)

18 Proteins Amino Acid (AAs) A building block of proteins 20 common AAs
Linked by condensation reaction – forms a peptide bond


20 Proteins Proteins come in a large variety of shapes + sizes
The number + sequence of AAs determines its shape

21 Proteins Enzyme Protein that changes the rate of the chemical reaction
May increase or decrease activity Activity of enzyme depends upon: Temperature Ionic conditions pH Works like a “lock + key” Example (p. 162)

22 Nucleic Acids Are necessary for life
Complex biomolecule that stores cellular information in the form of a code

23 Nucleic Acids Nucleotide A building block of nucleic acids
Composed of C, H, O, N, + Phosphorus (P) Arranged in 3 groups: Nitrogenous base Simple sugar Phosphate group

24 Nucleic Acids Types of Nucleic Acids DNA RNA Deoxyribonucleic acid
Master copy of organism’s information (appearance + behavior) Contains the instructions to be used by cell Passed down as cell divides RNA Ribonucleic acid Formed from DNA to make proteins


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